Nozzle



April 15, 1941. 1 M. FORSTER NOZZLE Filed April 10, 1939 wllf ' INVENTOR P520 Y M P0257272 ATTORNEY Patented Apr. 15, 1941 UNITED STATES PATENTOFFICE 3 Claims.

My invention relates to nozzles, and particularly to a form of nozzleproducing a long, finepointed flame.

The interior construction of a torch tip is of vital importance in theoutline of the flame cone. The form of tip which I have developed isadapted to give a long needle-like flame which is so concentrated in itsheating action that a piece of I paper may be held immediately adjacentthe flame cone near the nozzle without burning or charring, and willmaintain this pointed shape at pressures ranging from 1 to 50 pounds persquare inch on the gas supply. There is a noticeable absence of sideflame.

The effect is produced, so near as-I am now able to determine, byproperly proportioning the length and diameter of the nozzle opening,and by providing a sharply defined shoulder immediately preceding theentry to that opening. The basic nozzle may be modified by adding an airintake portion when pure gas is used, or used without such intake whenthe with compressed air.

The objects of my invention are:

To provide a nozzle in which the flame, regardless of pressure, does notleave the tip;

To provide a flame of. defined form which is unchanged by pressurevariations on the gas supp y;

To provide a form of nozzle which produces a sharply pointed flame cone;

To project a pointed flame which concentrates its heat in the flamecone;

To provide a nozzle which limits the flame heat to the cone only;

To provide a concentrating nozzle requiring no adjustments;

To eliminate the effect of variations inpressure of the gas source onthe shape of a flame; and

To produce a nozzle of preferred characteristics in a simple manner fromeasily procurable materials.

The invention possesses other objects and features of advantage, some ofwhich, with the foregoing, will be set forth in the followingdescription of a preferred form of my invention which is illustrated inthe drawing accompanying and forming a part of the specification. It isto'be understood that I do not limit myself to the showing made by thedrawing and description as I may adapt a variation of the preferred formwithin the scope of my invention as set forth in the claims.

My invention may be better understood by reference to the drawing, inwhich Fig. 1 is a perspective view of a preferred form of my nozzle,arranged to burn a mixture of gas and air;

Fig. 2 is a separated, in-line, view of the elegas is pre-mixed ments ofthe nozzle of Fig. 1, shown partially in section;

Fig. 3 is a sectional view of an element of my nozzle, taken in thedirection indicated by arrows 3-3 in Fig. 2;

Fig. 4 is a perspective view of a modification of my nozzle arranged toburn gas and air;

Fig. 5 is a sectional view of an element of the nozzle shown in Fig. 4;v

Fig. 61s a sectional view of the nozzle assembly of Fig. 4; and

Fig. 7 is a sectional view of a modification for use with larger nozzlebore diameters.

Referring now to Figs. 1 and 2, an inlet housing comprises a cylindricalshell 2 internally threaded to form an inlet port I which is surroundedby an end face 28 and may be screwed onto a supply line connected to asource of gas and air, not shown. Forwardly from port 4, the diameter ofthe bore is increased, and a short smooth-bored section 5 carried into athreaded portion 6 arranged to receive grid housing 1.

Externally threaded grid housing I is screwed .into the threaded portion6 of housing I. Grid housing I has a cylindrical bore 8 closed at theend nearest body I by a thick wall 9. Wall 9 is perforated by aplurality of apertures In parallel to the axis of the bore 8, andconstitutes a grid to break up and spread the gas stream coming throughinlet aperture 4. The threaded housing 1 is of sufficient length toscrew tightly into the housing I and still leave threads exposed ontowhich may be screwed a nozzle tip if, over an unthreaded terminalportion ll of grid housing I.

The nozzle tip l2 comprises the internally threaded cylindrical portionH which fits over the grid housing I, and a tapered nose l5. Within thenose I5 is a bore it, which is reduced abruptly'in diameter from that ofthreaded por tion I4 by a sharp shoulder H. The presence of thisshoulder-seems to be essential to the proper functioning of my device.

The bore l6 should preferably be in diameter, and I have found thisdimension to be some what criticalin producing the desired result.

The corresponding dimension for the length of the bore I6 isapproximately from A to 's";

If the length is less than this figure, the flame spreads out beyond thenozzle tip and the heat is not concentrated, but can be felt on allsides. If the length is greater than these limits, the flame tends toleave the tip and may go out entirely.

In Figs. 4, 5, and 6, the device is shown modified to permit its usewith a straight gas co'nnecti-on, drawing the oxygen for combustion fromthe air.

The form shown in Fig. 4 is secured by adding the element of Fig. 5 tothe basic form of Fig. 1. Th adapter 20 shown in Fig. 5 consists of abody 2! which has projecting forwardly therefrom a cylindrical section22 threaded to fit within the port 4 of the inlet housing I and havingan unthreaded portion 24 extending therebeyond of sufiicient length toalmost engage the grid 9 when the threaded portion 22 has been screwedinto the threaded inlet aperture 4 as far as possible, this distancebeing determined by the engagement of a shoulder 25 with the end face 26of housing Rearwardly from the shoulder 25, a nut portion 21, which maybe of hexagonal or other shape, isformed about the cylindrical portionfor engagement with a wrench or other tool to secure a tight fit, andthe adapter is continued cylindrically beyond the nut portion .21,terminating in a cylindrical portion 28. Cy-

lindrical portion 28 is internally threaded to engage with a gas fittingnot shown in the figure, and the chamber portion 29 surrounded by thethreaded end is forwardly terminated by a conical surface 30 at the apexof which an oriflce 3| is drilled. The diameter of orifice 3| may befrom .004 to .006 inch. A smaller diameter may admit insufficient gas topermit lighting the flame, and a larger diameter will admit so much gasthat the mixture is excessively rich. These values are applicableparticularly when the range of pressures on thegas supply varies betweenone and fifty pounds per square inch.

The orifice 3| extends forwardly from the conical surface 30 for only ashort distance, roughly 3 of an inch, where it enters the end of centerbore 35. A number of symmetrically spaced suction ports 32 are drilledthrough the element 20. These ports may be slightly larger than 1 3' ofan inch in diameter, and their common intersection results in anexpansion chamber 34, which, in accord with the well-known principles ofgaseous flow, acts to reduce the pressure immediately beyond the orifice3| and to cause an inspiration of air from the surrounding atmospherethrough ports 32. This air will join the gaseous fuel and mix therewithas thecombination passes down a center bore 35 which extends forwardlythroughout the remainder of the cylindrical portions 22 and 24 inalinement with the axis thereof.

It'will be obvious to those familiar with the art that. the constructiondescribed produces a simple venturi throat at the orifice 3|, thedownstream expanded portion 34 being formed by the intersection of bores32; and in consequence, over a considerable range of gas pressures,sufllcient air will be drawn in through the ports 32 to insure propercombustion when the mixture is ignited at the nozzle tip i5.

When it is desired to have a larger flame and still retain theadvantagesof my invention, a tip of the form shown in Fig. '7 may beused. This form differs from that of Fig. 6 by the greater diameter ofthe nozzle bore 40, which may be as much as /2 inch or more, and by thepresence of a second grid 4|. The second grid 4| is desirable to keepthe flame from blowing away from the nozzle tip. With this construction,I find it is preferable to use a bore 40 about equal in length to thediameter. However, as the sizes increase I find the general proportionsset out for the 3% of an inch size are satisfactory. The constructiondescribed has no moving parts and its effectiveness in operation overthe range of pressures between one and fifty pounds per square inch isapparently dependent in large part upon the proper proportioning betweenthe diameters of the nozzle aperture in nose I! and the length thereof.Another feature which now set forth include modifications of the intakeaperture designed to secure sufficient air for combustion, and the exactshape and dimensions of the elements shown. It is also to be understoodthat other variations may be made in my design which are within thescope of a mechanic skilled in the arts to which my design appertalns,and I intend that all such variations shall be covered by the claims.

I claim:

1. A burner nozzle adapted to produce a fine pointed flame at widelyvarying pressures comprising a body member having an orifice tip with asubstantially cylindrical inner bore, a cylindrical chamber adjacentsaid bore, larger than the latter and having a substantially rightangular wall adjacent the end of said cylindrical bore, the cylindricalwall of said chamber being imperforate, a grid forming an intermediatewall in said chamber and having a. central bore of materially greaterdiameter than the grid openings which are spaced radially therefrom, andmeans for conducting a combustible mixture into said chamber in linewith said central bore.

2. A burner nozzle adapted to produce a fine pointed flame at widelyvarying pressures comprising a body memberhaving an orifice tip with asubstantially cylindrical inner bore and a tapered outer portion, acylindrical chamber adjacent said bore, larger than the latter andhaving a substantially right angular front wall adjacent the end of saidcylindrical bore and an apertured rear wall, the cylindrical wall ofsaid chamber being imperforate, a grid extending across said chamberbetween said front and rear walls and having a central bore, and aplurality of bores of smaller diameter spaced radially therefrom, andmeans for conducting a combustible mixture into said chamber throughsaid apertured rear wall and in line with said central bore.

3. A burner nozzle adapted to produce a fine pointed flame at widelyvarying pressures comprising a body member having an orifice tip with asubstantially cylindrical inner bore with its axial length notsubstantially exceeding its diameter nor substantially less than half ofsaid diameter, a cylindrical chamber adjacent said bore, larger than thelatter and having a substantially right angular front wall adjacent theend of said cylindrical bore, the cylindrical wall of said chamber beingimperforate, a grid extending across said chamber and having arelatively large central bore and a plurality of bores of smallerdiameter spaced radially therefrom, and means for conducting acombustible mixture intosaid chamber in line with said central bore.

PERCY M. FORS'IER.

